For example, partly identical or similar patterns such as images of similar scenes in a video (a collective time section in the video), a logo of a company name in a commercial, and a characters or pattern indicating an owner inserted in an image may be included in different images. In most cases, these similar patterns used because they are related to each image or video to a certain extent. If the similarity can be detected and evaluated, search for and classification or collection of related image or video scenes can be realized.
As a specific example, FIGS. 1A and 1B show different images in which the same logo “ABE” is inserted. Such a logo represents, for example, information of an owner of the two images or an enterprise providing a product of a commercial image. As in this case, substantially the same logo may be inserted at different positions in the images. Usually, however, the positions where such a logo is inserted cannot be specified in advance and what pattern is inserted cannot be known in advance, either.
Not only a logo but also the same person, animal, object or background may be inserted in different images or videos.
Meanwhile, as a conventional method for searching for such a similar pattern, the pattern is separately prepared in advance by a certain technique and the pattern id detected by a correlative method, a histogram comparison method or the like.
For example, the Publication of Japanese Laid-Open Patent Application No. 2000-312343 discloses a technique of fast search for the same image as an image that is registered in advance. However, this requires preparation of the same image as the image to be searched for, in advance. Moreover, this technique cannot be applied to detection of a partly similar image constituting a video.
The Publication of Japanese Laid-Open Patent Application No. H11-328311 discloses a technique of detecting a pattern similar to a registered pattern using a correlative method in the case where such a similar pattern exists at a certain position another image. However, also this technique requires registration of the similar pattern in advance and it fails to detect and evaluate partial similarity between two arbitrary images from which a similar pattern cannot be found in advance.